Fluid-pressure brake.



GK OPPERMANN.

FLUID PRESSURE BRAKE.

APPLIOATION Hmm JULY 25. 1910.

1,081,325. Patented Dec. 16, 1913.

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GEORG OPPERMANN, OF HANOVER, GERMANY, ASSIGNOR TO THE WESTINGHOUSE AIR BRAKE COMPANY, OF PITTSIBURGH, EN'NSYLVcNIA, A CORPORATION 0F .PENN- SYLVANIA.

FLUID-PRESSURE BRAKE.

To all whom t may concern Be it known that I, Grone .OPPERMANM a subject of the Emperor of Germany, residing in the city of Hanover, Germany, have invented a certain new and useful Improve ment in Fluid-Pressure Brakes, of which improvement the following is a specification.

This invention relates to fluid pressure brakes, and more particularly to a valve device for regulating the flow of air to the brake cylinder in making an application of the brakes.

With the usual standard automat-ic brake equipment when a reduction in train pipe pressure is made to effect an application of the brakes, particularly an emergency application, fluid is rapidly supplied from the auxiliary reservoir and the train pipe to the brake cylinder, and the brake cylinders at the head end of the train are charged to the full equalized pressure before the brake pistons at the rear of the train have been pushed out suilieiently to apply the brake shoes to the wheels. As a consequence, the brake application is unevenly distributed through the train and violent shocks are apt to be produced.

The principal object of my invention is to provide means for first supplying fluid to the brake cylinder through the usual large opening and then when the brake cylinder pressure has reached a predetermined degrec, to automatically restrict the supply opening to the brake cylinder, so as to permit the brake cylinders on the rear cars to become charged with a certain degree of pressure before the brake cylinders on the head cars are fully charged, thus securing a more nearly simultaneous application of the brakes throughout the train.

In the accompanying drawings; Figure 1 is a central sectional view of an automatic brake equipment with my improvement applied thereto; Fig. 2 a detail sectional view of one of the piston heads of the pressure regulating device; Fig. 3 a central sectional view of an automatic car brake equipment showing a modified form of my invention applied thereto; and Fig. 4e a similar view showing another modified form of my improvement.

Fig. 1 shows a brake cylinder 1 with a screwed on admission regulator 2, which is connected by a pipe 3 with the triple valve Specification of Letters Patent.

Application lcd .'uly 25, 1910.

Patented Uec. 16,1913.

Serial No. 573,797.

el, the triple valve l being also connected by a pipe 5 to the train pipe and by a pipe G to the auxiliary air reservoir. The admis sion regulator 2 has two pistons 7 and 8 of different sizes, fastened to the same rod, and adapted to operate the slide valve 9.

`When a reduction of pressure is made in the train pipe, the triple valve 4 in the well known manner allows compressed air to fiow into the brake cylinder 1 from the auxiliary air reservoir and from the train pipe. rlhe admission of compressed air to the cylinder 1 from both the auxiliary reservoir and the train pipe may be effected entirely through the pipe 3, or through separate passages. The reservoir air can, for instance,

be conducted through the triple valve 1 and the passage 15, shown by dotted lines to the brake piston 1G, while the train pipe air is conducted through the triple valve, the pipe 3, and the admission regulator The compressed air admitted to the pipe 3, flows to the space between the pistons 7 and 8 of the admission regulator 2, presses the slide valve 9 to its seat and drives the pistons, together with the slide valve 9, to the position shown, as the piston 7 offers the inflowing compressed air a larger pressure face than the smaller piston 8 and because at the start only the pressure of the atmosphere rests on the outer faces of both pistons. The compressed air flowing from pipe 3 then flows through the passages 13, 11 and 35 to the brake cylinder, drives the brake piston forward and presses the brake shoes to the wheels. The chamber 10 is now connected through the passage 11, and cavity 30 in slide valve 9 with an atmospheric exhaust port 12.

The How of air into the brake cylinder causes the pressure of air between pistons 7 and S of the admission regulator to gradually decrease, while on the outer face of the piston 7 the brake cylinder pressure increasing. As soon as the brake cylinder pressure has increased to point such that in conjunction with the compressed air operating in the same direction on the piston 8 it overcomes the oppositely directed pressure of the compressed air from the triple valve on the piston 7 and the pressure of the atmosphere on the outer surface of the piston 8, it arises the pistons 7 and 8 with the slide valve 9 so that the piston closes the passage 14, as shown in Fig. 2, and the compressed air flowing through pipe 3 can now only flow through a restricted passage 13 in piston head 7 to the brake cylinder. The initial quick flow of compressed air to the brake cylinder is therefore now cut off. In order to tightly close the piston 7 at the circumference, the same may be provided with a valve seat, as shown in Fig. 2.

If it is desired to entirely cut off the flow of air from pipe 3 to the brake cylinder, the passage 13 through piston 7 may be omitted.-

The degree of pressure attained in the brake cylinder before the admission regulator 2 operates to close passage 14C, depends upon the relative sizes of the pistons 7 and 8. rI'he greater' the piston 7 in comparison to the piston 8, the higher is the pressure in the brake cylinder before the shift-ing of the pistons takes place. By a suitable choicen of the sizes of pistons 7 and 8 it is possible to provide that any desired proportion of the pressure flowing through the admission regulator shall flow quickly into the brake cylinder, the further flow of pressure to the cylinder in this direction being restricted or entirely cut off.

Fig. 3 shows the admission regulator in another form. In this construction, the smallpiston 18 forms a cylindrical body atthe lower end of which is placed the larger piston 19. The chamber 10 of the construction shown in Fig. 1, in this form is omitted and the outer face of the piston 18 is brought into direct communication with the atmosphere. rI`he compressed air admitted from the triple valve 4 to the pipe 3 flows into the ring shaped space 20 intermediate the pistons 18 and 19 and presses the pistons 18 and 19 downwardly, as below the same only the pressure of the atmosphere at first obtains. Then the compressed air flowing from the triple valve 4 passes through passages 21 and 22 and the passage 23 to the brake cylinder. As soon as the brake cylinder pressure acting below the piston 19 has increased so that it overcomes the differential pressure of the compressed air in the ring shaped space 20, said pressure lifts the pistons 18 and 19 to the position shown in Fig. 3. The large passage 22 is thereby closed and the compressed air coming from the triple valve l can therefore now only flow slowly through the restricted passage 21 to the brake cylinder 1. In this construction also, by suitably proportioning the relative sizes of pistons 18 and 19 it is possible to determine what proportion of the pressure flowing from pipe 3 shall be initially admitted to the brake cylinder before the passage 22 is closed and the further supply of pressure to the brake cylinder is restricted.

According to the construction shown in Fig. l of the drawing, a separate release pipe 25 may be employed, while pipe 24e is connected to the brake cylinder supply port of the triple valve device. The release pipe 25 is connected in t-he release position of the triple valve to the usual triple valve exhaustport while in making an application of the brakes said pipe is adapted to be connected to the train pipe, so that air vented from the train pipe flows through the pipe 25 to the brake cylinder. If desired, the reservoir supply pipe 24' may also be connected to the exhaust in the release position of the triple valve. The admission regulator 26 operates in the same way as described with regard to Fig. 3. The piston 27 however is not connected directly to the atmosphere but with a chamber 29 which is always at atmospheric pressure. If by reason of leakage during the braking, fluid under pressure should flow into this chamber, the action of the regulator is not thereby altered, if this eX- cess pressure is allowed to escape, when the brakes are released.

The relative distribution of fluid pressure on the faces of the regulator pistons with each modification, is such as to require only comparatively small pistons, and therefore a simple and compact construction is provided and the escape of compressed air to the atmosphere prevented as much as possible.

If separate air paths from t-he train pipe and from the auxiliary air reservoir to the brake cylinder are provided, it is possible, by providing a regulator valve in each air path, to regulate the supply of pressure to the brake cylinder in any desired manner and thereby control the entire braking action for the various purposes desired or the size of the brake cylinders, without altering the construction of the triple valves employed therewith. All vehicles can therefore be provided with t-he same triple valve without distinction, for instance, whether they are intended for long or short trains and whether they have large or small brake cylinders, for the currents of air conducted from the triple valves on both paths to the appertaining brake cylinders can each for itself, affected by the correspondingly proportioned passages and piston sizes of their admission regulators, be admitted more or less quickly to the cylinders, as may seem desirable for the given conditions for each of these paths.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is

1. In a fluid pressure brake, the combination with a brake cylinder, of means for supplying fluid from the train pipe to the brake cylinder in applying the brakes and operating at a predetermined degree of pressure in the brake cylinder to restrict the flow of air from the train pipe to the brake cylinder.

2. In a fluid pressure brake, the combination with a brake cylinder, of a valve device for controlling the supply of air from the train pipe to the brake cylinder and operated loy u predetermined degree of pressure in the brake cylinder for restricting the iiovv of air to the brake cylinder.

3. ln e fiuid pressure brake, the combination with a brake cylinder, of a Valve device for regulating the ioW or' air to Jche brake cylinder, Comprising e piston having differential piston heads subject on its dli'erential aree to the flow of Huid to the brake cylinder tending to maintain open communication for the flow of Huid to the brake cylinder and to the opposing pressure of the brake cylinder tending to close said communication.

4. ln e fluid pressure brake, the combinetion With u brake cylinder and a triple valve device for centrollinor the supply of air to the brake cylinder, ot e vulve device having diiferential piston heads subject to the opposing pressure of the brake cylinder and that of the fluid iiowing to Jelle brake cylinder for restricting the flow of ir from the triple vulve device to the brake cylinder.

5. In e fluid pressure brake, the combination with e, brake cylinder, of a differential piston device having its diillerentiul aree subject to the How oi air to the brake cylinder und subject on one side to the pressure in the brake cylinder for controlling the supply of air to the brake cylinder, said device operating ut u predetermined degree of pressure in the brake cylinder to restrict the flow of air to said brake cylinder.

ln testimony whereof l have hereunto set my hand.

GEORG OPPERMANN. Witnesses:

R. l?. TI-roMrsoN, R. V. BLoN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Iacents, Washington, I). C. 

